Hi Guys,
I recently got a Scott Bonnar Greenkeeper mower to refurbish and move onto a new home. It has a standard Chonda engine which I am pretty sure is a copy of the GXV140.
The mower is in excellent condition and had very little work. Despite my best efforts to date engine the starts popping out the carb with a slight surge once it is warmed up. The mower starts very easily and runs excellently until it gets hot.
To date I have done the following:
1) Cleaned the carb thoroughly including the main jet and emulsifier with the correct carb cleaning tools. I get nice easy one pull starts.
2) Adjusted the valves � they virtually had no clearance whatsoever. Intake - .15mm Exhaust - .20mm
3) Cleaned the magneto as it had some surface rust. Also re-gapped the magneto as the gap was huge between the flywheel.
4) New NGK Spark plug
5) Compression registers at about 120 odd psi
6) Top and bottom crankcase seals in excellent condition
7) All governor linkages are functioning correctly. The choke is also set up perfectly with nice easy one pull starts.
8) Air filter has been washed and re-oiled.
My thinking is the magneto might be giving up as the mower only starts to surge/ pop/ backfire when it gets hot.
I�d love some other suggestions as this one has me a little frustrated. I�ll put some photos up after work.
